Hydrogen gas dispensing systems and methods

ABSTRACT

According to at least one aspect, a hydrogen gas dispensing system is provided. The hydrogen gas dispensing system includes a source configured to provide a hydrogen gas, a storage device configured to store the hydrogen gas up to a first pressure level, a dispenser configured to dispense the hydrogen gas up to a second pressure level that is higher than the first pressure level, and a compressor configured to compress the hydrogen gas from the source up to the first pressure level for storage in the storage device and configured to compress the hydrogen gas from the storage device up to the second pressure level for dispensing via the dispenser. According to at least one aspect, the dispensing system comprises an input power port configured to receive input power and an output power port configured to deliver output power derived from the input power to charge an electric vehicle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. § 119(e) of each ofU.S. Provisional Application Ser. No. 62/447,400, titled “HYDROGEN FUELCELL REFUELER SYSTEM AND METHODS” filed on Jan. 17, 2017, U.S.Provisional Application Ser. No. 62/447,874, titled “HYDROGEN FUEL CELLREFUELER SYSTEM AND METHODS” filed on Jan. 18, 2017, U.S. ProvisionalApplication Ser. No. 62/455,308, titled “HYDROGEN FUEL CELL REFUELERSYSTEM AND METHODS” filed on Feb. 6, 2017, and U.S. ProvisionalApplication Ser. No. 62/489,219, titled “HYDROGEN DISPENSING METHODS ANDAPPARATUS” filed on Apr. 24, 2017, each of which is hereby incorporatedherein by reference in its entirety.

BACKGROUND

Hydrogen fuel cell vehicles (HFCV) are emerging as a zero-emissionalternative to internal combustion engine vehicles. HFCVs operate byproviding compressed hydrogen to a fuel cell stack which converts thehydrogen into electricity to drive an electric motor. Similar tointernal combustion engine vehicles, HFCVs are equipped with fuel tanksthat must be refilled periodically. In an effort to emulate therefueling paradigm and user experience of traditional gasoline refuelingstations, conventional hydrogen refueling stations are large capacity,complex, and expensive facilities. In particular, conventional hydrogenrefueling stations are designed to service regular vehicle traffic and,therefore, require large storage capacity to ensure continuous fuelavailability. Such large storage capacity is expensive, needs asignificant footprint, and requires extensive safety measures to be putinto place. In addition, to achieve fill times comparable to traditionalinternal combustion engine vehicles, expensive and complex coolingsystems must be implemented to prevent overheating when the compressedhydrogen is dispensed into the fuel tank of the HFCV.

SUMMARY

According to at least one aspect, a hydrogen gas dispensing system isprovided. The hydrogen gas dispensing system comprises: a sourceconfigured to provide hydrogen gas; a storage device configured to storethe hydrogen gas up to a first pressure level; a dispenser configured todispense the hydrogen gas up to a second pressure level that is higherthan the first pressure level; and a compressor fluidly coupled to thesource, the storage device, and the dispenser, the compressor configuredto compress the hydrogen gas from the source up to the first pressurelevel for storage and configured to compress the hydrogen gas from thestorage device up to the second pressure level for dispensing via thedispenser.

In some embodiments, the system further comprising a controllerconfigured to detect a storage pressure level of the storage device whena vehicle is coupled to the hydrogen gas dispensing system via thedispenser, the controller further configured to: cause hydrogen gas toflow from the storage device to a fuel tank of the vehicle via thedispenser when the storage pressure level is greater than a thresholdpressure level; and cause hydrogen gas from the storage device to becompressed by the compressor before being dispensed to the fuel tank ofthe vehicle via the dispenser when the storage pressure level is lessthan the threshold pressure level.

In some embodiments, the controller is configured to detect a vehiclepressure level of the fuel tank of the vehicle coupled to the coupled tothe hydrogen gas dispensing system via the dispenser, and wherein thethreshold pressure level is relative to the vehicle pressure level. Insome embodiments, the threshold pressure level is substantially thevehicle pressure level of the fuel tank. In some embodiments, the sourcecomprises an external source of hydrogen gas.

In some embodiments, the first pressure level is greater than or equalto approximately 5,000 and less than or equal to approximately 8,000pounds per square inch (PSI) and the second pressure level is greaterthan or equal to approximately 8,000 PSI and less than or equal toapproximately 12,000 PSI. In some embodiments, the first pressure levelis approximately 6,000 pounds per square inch (PSI) and the secondpressure level is approximately 10,000 PSI.

In some embodiments, the storage device comprises a plurality of storagetanks. In some embodiments, the system further comprises a fireretardant material that at least partially encloses the storage device.In some embodiments, the storage device is configured to store no morethan approximately 10 kilograms of hydrogen gas.

In some embodiments, the source comprises an electrolyzer configured toreceive water and produce the hydrogen gas using the water. In someembodiments, the system further comprises a hydrogen gas purifierfluidly coupled between the electrolyzer and the compressor, thehydrogen gas purifier being configured to remove at least some oxygenand/or at least some water from the hydrogen gas produced by theelectrolyzer.

In some embodiments, the system further comprises an enclosure encasingat least the storage device and comprising an air vent; and an aircirculation device disposed in the enclosure and configured to provideventilation for the enclosure. In some embodiments, the air circulationdevice comprises at least one fan arranged to force air from inside theenclosure to an external environment through the air vent.

In some embodiments, the system further comprises: a hydrogen gas sensordisposed in the enclosure and configured to detect hydrogen gas in theenclosure; and a circuit communicatively coupled to the hydrogen gassensor and configured to shut down at least one component of thehydrogen gas dispensing system when a hydrogen gas concentrationdetected by the hydrogen gas sensor exceeds a threshold.

In some embodiments, the system further comprises: a pressure sensordisposed in the enclosure and configured to measure a change in airpressure caused by air being forced through the air vent; and a circuitcommunicatively coupled to the air pressure sensor and configured toshut down at least one component of the hydrogen gas dispensing systemwhen an air pressure level detected by the air pressure sensor indicatesan issue with air circulation.

In some embodiments, the system further comprises: a temperature sensordisposed in the enclosure and configured to measure a temperature of airin the enclosure; and a circuit communicatively coupled to thetemperature sensor and configured to shut down at least one component ofthe hydrogen gas dispensing system when a temperature level detected bythe temperature sensor exceeds a threshold.

In some embodiments, the system further comprises: a heater disposed inthe enclosure; a temperature sensor disposed in the enclosure andconfigured to measure a temperature of air in the enclosure; and acircuit communicatively coupled to the temperature sensor and theheater, the circuit being configured to control operation of the heaterbased on a temperature level detected by the temperature sensor.

In some embodiments, the enclosure comprises: a first compartment havingat least the storage device disposed therein; a second compartmenthaving at least the electrolyzer disposed therein; and a fire retardantmaterial disposed between the first compartment and the secondcompartment.

In some embodiments, the system further comprises a safety system forcontrolling powering and depowering components of the hydrogen gasdispensing system, the safety system comprising: the air circulationdevice; a pressure sensor disposed in the enclosure and configured tomeasure a change in air pressure to confirm correct operation of the aircirculation device; a hydrogen gas sensor disposed in the enclosure andconfigured to detect hydrogen gas in the enclosure; a temperature sensordisposed in the enclosure and configured to measure a temperature of airin the enclosure; and a safety controller coupled to the pressuresensor, the hydrogen gas sensor and the temperature sensor andconfigured to provide power to components of the hydrogen gas dispensingsystem, wherein the safety controller is configured to power and depowercomponents of the hydrogen gas dispensing system based, at least inpart, on indications received from the pressure sensor, the hydrogen gassensor and the temperature sensor.

In some embodiments, upon power up of the hydrogen gas dispensingsystem, the safety controller engages the air circulation device, thepressure sensor, the hydrogen gas sensor and the temperature sensor andprovides operational power to other components of the hydrogen gasdispensing system only when the safety system confirms safe operation.In some embodiments, the safety controller is configured to power downthe hydrogen gas dispensing system if any of the pressure sensor,hydrogen gas sensor and/or temperature sensor signal unsafe operatingconditions.

In some embodiments, the hydrogen gas dispensing system is configured toprovide a visual indication of a fill level of the storage device. Insome embodiments, the system further comprises: a lighting systemconfigured to provide light in a selected one of a plurality of colorsbased on a control signal; and a circuit coupled to the lighting systemand configured to generate the control signal based on the fill level ofthe storage device.

In some embodiments, the system further comprises: an input power portconfigured to receive input power from a power source; and an outputpower port configured to deliver output power derived from the inputpower received at the input power port to charge an electric vehicle.

In some embodiments, the input power port is configured to receivesingle-phase mains electricity from the power source. In someembodiments, the output power port is configured to deliver output powersuitable for level-1 charging of the electric vehicle. In someembodiments, the input power port is configured to receive single-phasemains electricity at approximately 120V and the output power port isconfigured to deliver power at approximately 120V to deliver level-1charging to the electric vehicle.

In some embodiments, the output power port is configured to deliveroutput power suitable for level-2 charging of the electric vehicle. Insome embodiments, the input power port is configured to receivesingle-phase mains electricity at approximately 240V and the outputpower port is configured to deliver power at approximately 240V todeliver level-2 charging to the electric vehicle.

In some embodiments, the system further comprises power conversioncircuitry configured to convert the input power into the output power.In some embodiments, the input power port is configured to receivethree-phase power from the power source and the power conversioncircuitry is configured to convert the three-phase power intosingle-phase power. In some embodiments, the power conversion circuitryis configured to convert the three-phase power into single-phase powersuitable for level-1 charging of the electric vehicle. In someembodiments, the power conversion circuitry is configured to convert thethree-phase power into single-phase power suitable for level-2 chargingof the electric vehicle.

In some embodiments, the input power is alternating current (AC),wherein the power conversion circuitry is configured to convert the ACinput power to direct current (DC) power. In some embodiments, the powerconversion circuitry is configured to convert the AC input power to DCoutput power suitable for fast DC charging of the electric vehicle.

According to at least one aspect, a method of operating a hydrogen gasdispensing system comprising a compressor is provided. The methodcomprises providing a hydrogen gas to the compressor; compressing thehydrogen gas from the source up to a first pressure level using thecompressor; storing the hydrogen gas from the compressor in a storagedevice; compressing the hydrogen gas from the storage device up to asecond pressure level that is higher than the first pressure level usingthe compressor; and dispensing the hydrogen gas from the compressor.

In some embodiments, providing the hydrogen gas to the compressorcomprises receiving water and generating the hydrogen gas by anelectrolyzer using the water. In some embodiments, storing the hydrogengas from the compressor in the storage device comprises storing no morethan approximately 10 kilograms of the hydrogen gas in the storagedevice. In some embodiments, the method further comprises measuring afill level of the storage device; and providing a visual indicating ofthe fill level of the storage device.

In some embodiments, the method further comprises forcing air frominside an enclosure comprising an air vent and encasing at least thestorage device to an external environment through the air vent. In someembodiments, the method further comprises detecting a presence ofhydrogen gas in air being forced through the air vent using the hydrogengas sensor and shutting down at least one component of the dispensingsystem when a hydrogen gas concentration detected by the hydrogen gassensor exceeds a threshold. In some embodiments, the method furthercomprises measuring a change in air pressure caused by air being forcedthrough the air vent using an air pressure sensor and shutting down atleast one component of the dispensing system when an air pressure leveldetected by the air pressure sensor indicates that air is not beingforced through the air vent.

In some embodiments, the method further comprises measuring atemperature of air in the enclosure using a temperature sensor; andshutting down at least one component of the hydrogen gas fueling systemwhen a temperature level detected by the temperature sensor exceeds athreshold. In some embodiments, the method further comprises measuring atemperature of air in the enclosure using a temperature sensor; andcontrol operation of heater disposed in the enclosure based on atemperature level detected by the temperature sensor.

According to at least one aspect, a hybrid dispensing system isprovided. The hybrid dispensing system comprises a source configured toprovide hydrogen gas, a storage device configured to store the hydrogengas, a dispenser configured to dispense the hydrogen gas, an input powerport configured to receive input power from a power source, and anoutput power port configured to deliver output power derived from theinput power received at the input power port to charge an electricvehicle.

In some embodiments, the storage device is configured to store thehydrogen gas up to a first pressure level, and the dispenser isconfigured to dispense the hydrogen gas up to a second pressure levelthat is higher than the first pressure level, the hybrid dispensingsystem further comprising a compressor fluidly coupled to the source,the storage device, and the dispenser, the compressor configured tocompress the hydrogen gas from the source up to the first pressure levelfor storage and configured to compress the hydrogen gas from the storagedevice up to the second pressure level for dispensing via the dispenser.

In some embodiments, the input power port is configured to receivesingle-phase mains electricity from the power source. In someembodiments, the output power port is configured to deliver output powersuitable for level-1 charging of the electric vehicle. In someembodiments, the input power port is configured to receive single-phasemains electricity at approximately 120V and the output power port isconfigured to deliver power at approximately 120V to deliver level-1charging to the electric vehicle. In some embodiments, the output powerport is configured to deliver output power suitable for level-2 chargingof the electric vehicle. In some embodiments, the input power port isconfigured to receive single-phase mains electricity at approximately240V and the output power port is configured to deliver power atapproximately 240V to deliver level-2 charging to the electric vehicle.

In some embodiments, the system further comprises power conversioncircuitry configured to convert the input power into the output power.In some embodiments, the input power port is configured to receivethree-phase power from the power source and the power conversioncircuitry is configured to convert the three-phase power intosingle-phase power. In some embodiments, the power conversion circuitryis configured to convert the three-phase power into single-phase powersuitable for level-1 charging of the electric vehicle. In someembodiments, the power conversion circuitry is configured to convert thethree-phase power into single-phase power suitable for level-2 chargingof the electric vehicle.

In some embodiments, the input power is alternating current (AC),wherein the power conversion circuitry is configured to convert the ACinput power to direct current (DC) power. In some embodiments, the powerconversion circuitry is configured to convert the AC input power to DCoutput power suitable for fast DC charging of the electric vehicle.

In some embodiments, the system further comprises a controllerconfigured to detect a storage pressure level of the storage device whena vehicle is coupled to the hydrogen gas dispensing system via thedispenser, the controller further configured to: cause hydrogen gas toflow from the storage device to a fuel tank of the vehicle via thedispenser when the storage pressure level is greater than a thresholdpressure level; and cause hydrogen gas from the storage device to becompressed by the compressor before being dispensed to the fuel tank ofthe vehicle via the dispenser when the storage pressure level is lessthan the threshold pressure level.

In some embodiments, the controller is configured to detect a vehiclepressure level of the fuel tank of the vehicle coupled to the coupled tothe hydrogen gas dispensing system via the dispenser, and wherein thethreshold pressure level is relative to the vehicle pressure level. Insome embodiments, the threshold pressure level is substantially thevehicle pressure level of the fuel tank. In some embodiments, the sourcecomprises an external source of hydrogen gas.

In some embodiments, the first pressure level is greater than or equalto approximately 5,000 and less than or equal to approximately 8,000pounds per square inch (PSI) and the second pressure level is greaterthan or equal to approximately 8,000 PSI and less than or equal toapproximately 12,000 PSI. In some embodiments, the first pressure levelis approximately 6,000 pounds per square inch (PSI) and the secondpressure level is approximately 10,000 PSI.

In some embodiments, the storage device comprises a plurality of storagetanks. In some embodiments, the system further comprises a fireretardant material that at least partially encloses the storage device.In some embodiments, the storage device is configured to store no morethan approximately 10 kilograms of hydrogen gas.

In some embodiments, the source comprises an electrolyzer configured toreceive water and produce the hydrogen gas using the water. In someembodiments, the system further comprises a hydrogen gas purifierfluidly coupled between the electrolyzer and the compressor, thehydrogen gas purifier being configured to remove at least some oxygenand/or at least some water from the hydrogen gas produced by theelectrolyzer.

In some embodiments, the system further comprises an enclosure encasingat least the storage device and comprising an air vent; and an aircirculation device disposed in the enclosure and configured to provideventilation for the enclosure. In some embodiments, the air circulationdevice comprises at least one fan arranged to force air from inside theenclosure to an external environment through the air vent.

In some embodiments, the system further comprises a hydrogen gas sensordisposed in the enclosure and configured to detect hydrogen gas in theenclosure; and a circuit communicatively coupled to the hydrogen gassensor and configured to shut down at least one component of thehydrogen gas dispensing system when a hydrogen gas concentrationdetected by the hydrogen gas sensor exceeds a threshold.

In some embodiments, the system further comprises a pressure sensordisposed in the enclosure and configured to measure a change in airpressure caused by air being forced through the air vent; and a circuitcommunicatively coupled to the air pressure sensor and configured toshut down at least one component of the hydrogen gas dispensing systemwhen an air pressure level detected by the air pressure sensor indicatesan issue with air circulation.

In some embodiments, the system further comprises a temperature sensordisposed in the enclosure and configured to measure a temperature of airin the enclosure; and a circuit communicatively coupled to thetemperature sensor and configured to shut down at least one component ofthe hydrogen gas dispensing system when a temperature level detected bythe temperature sensor exceeds a threshold.

In some embodiments, the system further comprises a heater disposed inthe enclosure; a temperature sensor disposed in the enclosure andconfigured to measure a temperature of air in the enclosure; and acircuit communicatively coupled to the temperature sensor and theheater, the circuit being configured to control operation of the heaterbased on a temperature level detected by the temperature sensor.

In some embodiments, the system further comprises a first compartmenthaving at least the storage device disposed therein; a secondcompartment having at least the electrolyzer disposed therein; and afire retardant material disposed between the first compartment and thesecond compartment.

In some embodiments, the system further comprises a safety system forcontrolling powering and depowering components of the hydrogen gasdispensing system, the safety system comprising: the air circulationdevice; a pressure sensor disposed in the enclosure and configured tomeasure a change in air pressure to confirm correct operation of the aircirculation device; a hydrogen gas sensor disposed in the enclosure andconfigured to detect hydrogen gas in the enclosure; a temperature sensordisposed in the enclosure and configured to measure a temperature of airin the enclosure; and a safety controller coupled to the pressuresensor, the hydrogen gas sensor and the temperature sensor andconfigured to provide power to components of the hydrogen gas dispensingsystem, wherein the safety controller is configured to power and depowercomponents of the hydrogen gas dispensing system based, at least inpart, on indications received from the pressure sensor, the hydrogen gassensor and the temperature sensor.

In some embodiments, upon power up of the hydrogen gas dispensingsystem, the safety controller engages the air circulation device, thepressure sensor, the hydrogen gas sensor and the temperature sensor andprovides operational power to other components of the hydrogen gasdispensing system only when the safety system confirms safe operation.In some embodiments, the safety controller is configured to power downthe hydrogen gas dispensing system if any of the pressure sensor,hydrogen gas sensor and/or temperature sensor signal unsafe operatingconditions. In some embodiments, the hydrogen gas dispensing system isconfigured to provide a visual indication of a fill level of the storagedevice.

In some embodiments, the system further comprises a lighting systemconfigured to provide light in a selected one of a plurality of colorsbased on a control signal; and a circuit coupled to the lighting systemand configured to generate the control signal based on the fill level ofthe storage device.

BRIEF DESCRIPTION OF DRAWINGS

Various aspects and embodiments of the disclosed technology will bedescribed with reference to the following figures. It should beappreciated that the figures are not necessarily drawn to scale. Itemsappearing in multiple figures are indicated by the same reference numberin all the figures in which they appear.

FIG. 1A illustrates a block diagram of an exemplary hydrogen gasdispensing system, in accordance with some embodiments;

FIG. 1B illustrates a block diagram of an exemplary hydrogen gasdispensing system, in accordance with some embodiments;

FIG. 2 illustrate a block diagram of an exemplary control system for theexemplary hydrogen gas dispensing system of FIG. 1A, in accordance withsome embodiments;

FIGS. 3A-3D illustrate views of an exemplary implementation of ahydrogen gas dispensing system as a hydrogen refueling appliance, inaccordance with some embodiments;

FIG. 4 illustrates exemplary internal layout a hydrogen refuelingappliance, in accordance with some embodiments;

FIG. 5 illustrates exemplary detailed internal layout of a hydrogenrefueling appliance, in accordance with some embodiments;

FIG. 6 illustrates a method of operating a hydrogen gas dispensingsystem, in accordance with some embodiments;

FIG. 7 illustrates a method of providing hydrogen to storage on ahydrogen gas dispensing system, in accordance with some embodiments;

FIG. 8 illustrates a method of dispensing hydrogen from a hydrogen gasdispensing system to a vehicle, in accordance with some embodiments;

FIG. 9 is a graph showing an example vehicle fill event performed by ahydrogen gas dispensing system, in accordance with some embodiments; and

FIG. 10 is a graph showing another example vehicle fill event performedby a hydrogen gas dispensing system, in accordance with someembodiments.

DETAILED DESCRIPTION

Conventional refueling stations for hydrogen fuel cell vehicles (HFCVs)are large, complex and expensive facilities patterned after refuelingstations for internal combustion engine powered vehicles. Suchfacilities are designed to provide essentially continuous availabilityand supply of fuel at fill times that are comparable to that ofgasoline, thus requiring large storage capacity and expensive coolingsystems. The inventors have recognized that while this paradigm is wellsuited for the petroleum based market, it is less suited to HFCVs due inpart to differences between storage and dispensing of gasoline andcompressed hydrogen and in part to differences between the respectivemarkets.

The inventors have developed a hydrogen gas dispensing system fordispensing compressed hydrogen to refill hydrogen tanks on HFCVs, inaccordance with some embodiments. The hydrogen gas dispensing system maybe advantageously designed as a stand-alone unit (e.g., a stand-alonehydrogen refueling appliance) that uses readily accessible resources,such as water and electricity, to generate hydrogen to refill hydrogentanks. Further, the hydrogen gas dispensing system may be constructed tohave a compact footprint. For example, the hydrogen gas dispensingsystem may require a footprint that is no larger than a single parkingspace (e.g., 9 feet by 18 feet). Thereby, the hydrogen gas dispensingsystem may be constructed at any location that has, for example, accessto a water line and a power line (e.g., a parking lot of a shoppingcenter, a parking garage for an office building, compact refuelingisland for a community or neighborhood, etc.). Accordingly, a hydrogenrefueling experience for a user may be provided that is similar to adestination charging experience for an electric vehicle. For example, auser can park their vehicle, connect their vehicle to the hydrogen gasdispensing system, and engage in other activities, such as shopping,working, or tasks around the house, while the hydrogen gas dispensingsystem refuels their vehicle. Given the relatively short fill times ofsome embodiments of the hydrogen gas dispensing systems describedherein, a consumer may also wait in proximity to the vehicle while itfills similar to the model for conventional gasoline stations.

In some embodiments, the hydrogen gas dispensing system may beconstructed to produce, compress, and dispense its own hydrogen to HFCVsusing only a connection to a water source (e.g., a connection to a townwater line) and a connection to a power source (e.g., a connection to apower grid, such as a three-phase power hook-up or a connection tosingle phase mains electricity). For example, the hydrogen gasdispensing system may comprise a hydrogen source that is configured togenerate hydrogen gas for the system, such as an electrolyzer thatseparates the hydrogen from water using electricity. The hydrogen gasfrom the hydrogen source may be compressed using a single or multiplestage compressor for storage in a storage device, such as a set of oneor more storage tanks. The hydrogen gas may be stored in the storagedevice at a lower pressure level than the maximum pressure at which thehydrogen gas may be dispensed to a HFCV via a dispenser to reduce thecost and complexity of the storage device and the dispenser. Forexample, the hydrogen gas may be stored up to a pressure ofapproximately 6,000 pounds per square inch (PSI) while the hydrogen gasdispensing system may dispense the hydrogen gas up to a pressure ofapproximately 10,000 PSI. The single or multiple stage compressor mayalso be configured to use some or all of its available compressionstages to boost the pressure of the hydrogen gas from the storage devicein cases where the pressure required to dispense the hydrogen gas to theHFCV is greater than the pressure at which the hydrogen gas is stored inthe storage device.

Additionally, the hydrogen gas dispensing system may advantageouslyinclude an electric vehicle charger with the hydrogen gas dispensingcomponents. For example, the hydrogen gas dispensing system may comprisea level-1 charger and/or a level-2 charger. Thereby, the hydrogen gasdispensing system may charge electric vehicles as well as refuel HFCVs(e.g., simultaneously and/or in direct succession). Further, theelectric vehicle charger may be integrated into the hydrogen gasdispensing system without a significant increase in cost, complexity, orsize. For example, the electric vehicle charger may be connected to thesame power source that provides power to the hydrogen gas dispensing orgeneration components in the hydrogen gas dispensing system. Thereby, noadditional power connections may be required.

Following below are more detailed descriptions of various conceptsrelated to, and embodiments of, hydrogen gas dispensing systems. Itshould be appreciated that the embodiments described herein may beimplemented in any of numerous ways. Examples of specificimplementations are provided below for illustrative purposes only. Itshould be appreciated that these embodiments and thefeatures/capabilities provided may be used individually, all together,or in any combination of two or more, as aspects of the technologydescribed herein are not limited in this respect.

FIG. 1A shows a block diagram of a hydrogen gas dispensing system 100that is configured to dispense hydrogen gas to a vehicle (e.g., a HFCV)using a dispenser 106 and/or provide power to a vehicle (e.g., anelectric vehicle or a HFCV) using a power output port 108. It should beappreciated that power output port 108 may be present in hybriddispensing systems configured to dispense hydrogen gas to HFCVs anddeliver electric power to charge batteries of electric or hybridvehicles, but may be omitted in hydrogen gas dispensing systems thatdispense hydrogen gas, but do not provide the ability to charge electriccar batteries. As shown, the system 100 comprises an electrolyzer 112 togenerate hydrogen gas using water from a water input port 104 and powerfrom a power input port 102. The water input port 104 and power inputport 102 can be any suitable connection that allows the hydrogen gasdispensing system 100 to connect to the respective source.

In the embodiment illustrated in FIG. 1A, the electrolyzer 112 incombination with the power input port 102 and the water input port 104form a hydrogen source 105 that is configured to provide hydrogen gas toone or more components in the hydrogen gas dispensing system 100.Electrolyzers are well-known components and any suitable type may beused as the electrolyzer 112. The electrolyzer 112 may be selected to beof a size and capacity suitable for the particular installment of system100. For example, the electrolyzer 112 may be of the size and capacityto fill storage system 122 from an empty to a full state inapproximately 48 hours, approximately 24 hours, approximately 12 hours,approximately 6 hours, etc., or any time that is suitable for therefueling paradigm of hydrogen gas dispensing system 100. The hydrogengas from the hydrogen gas source 105 (e.g., hydrogen gas produced byelectrolyzer 112) may be purified by a gas purifier 114 before beingprovided to downstream components of the system. According to someembodiments, gas purifier 114 may be unnecessary. For example, accordingto some embodiments, electrolyzer 112 may produce hydrogen gas at asufficient purity so that further purification stage(s) may not beneeded. In embodiments that utilize a gas purifier, gas purifier 114 maybe configured to purify the hydrogen gas from the hydrogen source 105 tomake the hydrogen gas suitable for filling a vehicle. The gas purifier114 may be configured to remove any of a variety of undesired componentsfrom the hydrogen gas provided by the hydrogen source 105. For example,the hydrogen gas from the source 105 may be mixed with water and the gaspurifier 114 may be configured to remove at least some of the water.

FIG. 1B illustrates an alternative embodiment of a hydrogen gasdispensing system 100′, wherein the hydrogen gas source 105′ comprises ahydrogen gas port configured to connect to an external hydrogen gassource, such as an external storage tank, external hydrogen gasgenerating facility, etc. Hydrogen gas dispensing system 100′ can beused in connection with an existing external hydrogen gas source to takeadvantage of the dispensing capabilities of the multi-functioncompressor discussed in further detail below. Hydrogen gas dispensingsystem 100′ is shown without a gas purifier as the external hydrogen gassource may produce hydrogen gas of sufficient purity. However, it shouldbe appreciated that a gas purifier (e.g., gas purifier 114 illustratedin connection with FIG. 1A) may alternatively be used to purify thehydrogen gas (e.g., to remove water or other impurities from thehydrogen gas), as the aspects are not limited in this respect.

In the embodiments illustrated in FIGS. 1A and 1B, the hydrogen gasdispensing system comprises a compressor 116 that is configured tofacilitate a dual mode refueling appliance. The compressor 116 mayreceive power from the power input port 102. The compressor 116 may beconfigured to compress the received hydrogen gas up to a first pressurelevel, such as approximately 6,000 PSI, for storage in a storage system122. It should be appreciated that the first pressure level may selectedas appropriate for a given dispensing system (e.g., in a range betweenapproximately 5,000 PSI and 8,000 PSI). The compressor 116 may befurther configured to compress the hydrogen gas from the storage 122 upto a second pressure level that is higher than the first pressure level,such as approximately 10,000 PSI, for dispensing using the dispenser 106(e.g., when the pressure in the tank of a HFCV is greater than thepressure of the hydrogen gas in storage 122). Similarly, the secondpressure level can be selected as appropriate for a given dispensingsystem (e.g., in a range between 6,000 PSI and 15,000 PSI).

As shown, the compressor 116 may comprise multiple stages including afirst stage 118 and a second stage 120. Each of the first and secondstages 118 and 120, respectively, may be configured to compress hydrogengas up to a different pressure level. For example, hydrogen gas from thehydrogen source 105 may be compressed to a first pressure level by thefirst stage 118 and further compressed to a second, higher pressurelevel by the second stage 120. The flow of hydrogen gas within thesystem 100 may be controlled by a set of flow control devices, shown asflow control devices 124, 125, and 126. The flow control device 124 maydirect hydrogen gas from the first stage 118 to the second stage 120 ofthe compressor in operation modes where hydrogen gas is being added tothe storage system 122 or direct the hydrogen gas from the first stage118 back to the first stage 118 in other operation modes (e.g., wherethe system 100 is dispensing hydrogen from the storage system 122). Theflow control device 125 may direct hydrogen gas from the second stage120 to the storage system 122 in operation modes where the storagesystem 122 is being filled or direct hydrogen gas from the second stage120 directly to the dispenser 106 in operation modes where the pressureof the hydrogen gas from the storage system 122 needs to be boosted bythe second stage 120 before going to dispenser 106. The flow controldevice 126 may direct hydrogen gas directly from the storage system 122to the dispenser 106 in operation modes where the second stage 120 isbypassed or direct the hydrogen gas to the second stage 120 in operationmodes where the pressure of the hydrogen gas from the storage system 122needs to be boosted by the second stage 120 before going to dispenser106.

The hydrogen gas dispensing system 100/100′ may further comprise acontrol system 110 to control the operation of one or more componentswithin the system 100/100′. According to some embodiments, controlsystem 110 may receive power from power input port 102.

As discussed above, the hydrogen source may generate hydrogen gas withinthe dispensing system (e.g., hydrogen source 105 comprising anelectrolyzer 112, power port 102 and water port 104) or may beconfigured to connect to an external hydrogen gas source (e.g., hydrogensource 105′ comprising a hydrogen gas port to connect to an externalsource), such as a large capacity storage tank that is located remotelyfrom the system. According to some embodiments, a hydrogen gasdispensing system may be configured to generate hydrogen gas internally(e.g., via an on-board electrolyzer) and configured to connect to anexternal hydrogen gas source. For example, hydrogen source 105illustrated in FIG. 1A may also include a hydrogen gas port 103 toconnect to an external hydrogen gas source, providing the option ofproducing hydrogen gas internally, connecting to an external source, orboth, providing a flexible system that can be utilized in a variety ofrefueling installations.

The compressor 116 may be configured to compress hydrogen gas forstorage in the storage system 122 and/or compress hydrogen gas fordispensing via the dispenser 106. The compressor 116 may have multiplestages, such as the first stage 118 and the second stage 120. Each ofthe stages in the compressor 116 may be configured to compress hydrogengas up to a different pressure level. For example, the first stage 118may be configured to compress hydrogen from the gas purifier 114 up to afirst pressure level and the second stage 120 that is configured tocompress hydrogen gas up to a second pressure level that is higher thanthe first pressure level. The design of the system 100 may permit thecompressor 116 to both compress hydrogen gas from the hydrogen source105 for application to the storage system 122 and to compress thehydrogen gas from the storage system 122 for dispensing. Such a designmay provide numerous benefits. For example, the system 100/100′ may beable to store the hydrogen gas in the storage system 122 at a lowerpressure than the maximum pressure at which hydrogen gas may bedispensed and, thereby, reduces the cost, complexity, and size of thesystem 100/100′. The relatively low pressure of the hydrogen gas storedon the system may simplify the safety measures needed to satisfy theregulatory requirements. Additionally, all (or nearly all) of thehydrogen gas from the storage system 122 may be dispensed regardless ofthe pressure differential between the pressure of the hydrogen in thestorage system 122 and the pressure in the tank into which the hydrogenis being dispensed. Thereby, the storage capacity of the storage system122 may be reduced without substantially impacting the performance ofthe system 100/100′. In this manner, the compressor may function toprovide a boost to utilize as much stored hydrogen gas as possibleand/or to provide the needed pressure to fill the tank of a HFCV.

It should be appreciated that the compressor 116 may have more or lessthan the two compressor stages shown in FIGS. 1A and 1B. For example,the storage system 122 may comprise two storage tanks that are eachconfigured to store hydrogen gas up to a different pressure level. Inthis example, the compressor 116 may use different combinations of itsstages to compress hydrogen up to a first pressure level for the firststorage tank, a second compressor stage to compress hydrogen up to asecond pressure level for the second storage tank, and a thirdcompressor stage to compress hydrogen up to a third pressure level fordispensing via the dispenser 106. In another example, the compressor 116may have only a single stage. In this example, the first stage 118 andthe flow control device 124 may be omitted from the system 100 and theoutput of the gas purifier 114 may be provided directly to the secondstage 120.

The flow control device 124 may be configured to direct hydrogen gasfrom the first stage 118 to the second stage 120 and/or back to thefirst stage 118. The flow control device 124 may be implemented as a setof one or more control valves that are configurable to control the flowof hydrogen gas depending on the operating conditions of the system. Forexample, the flow control device 124 may be controlled to be in a firstconfiguration wherein the output of the first stage 118 is connected tothe second stage 120 and controlled to be in a second configurationwherein the output of the first stage 118 is directed back to the firststage 118. The control valve(s) may be placed in the first configurationmay when the system 100/100′ is storing generated and/or receivedhydrogen gas in storage system 122. The control valve(s) may be placedin the second configuration in other instances such as when the secondstage 120 is boosting the pressure of hydrogen from the storage system122 for dispensing via dispenser 106. The configuration of the flowcontrol device 124 may be controlled by, for example, one or morecontrol signals received from the control system 110.

The flow control device 125 may be configured to direct hydrogen gasfrom the second stage 120 and/or to the dispenser 106. The flow controldevice 125 may be implemented as a set of one or more control valvesthat are configurable to control the flow of hydrogen gas depending onthe operating conditions of the system. For example, the flow controldevice 125 may be controlled to be in a first configuration wherein theoutput of the second stage 120 is connected to the dispenser 106 andcontrolled to be in a second configuration wherein the output of thesecond stage 120 is directed to the storage system 122. The controlvalve(s) may be placed in the first configuration may when the system100/100′ is storing generated and/or received hydrogen gas in storagesystem 122. The control valve(s) may be placed in the secondconfiguration in other instances such as when the second stage 120 isboosting the pressure of hydrogen from the storage system 122 fordispensing via dispenser 106. The configuration of the flow controldevice 125 may be controlled by, for example, one or more controlsignals received from the control system 110.

The flow control device 126 may be configured to direct hydrogen gasfrom the storage device 122 to the dispenser 106 and/or the second stage120. The flow control device 126 may be implemented as a set of one ormore control valves that are configurable to control the flow ofhydrogen gas during dispensing. For example, the flow control device 126may be controlled to be in a first configuration wherein the output ofthe storage device 122 is connected to the dispenser 106 (e.g., hydrogengas bypasses the second stage 120) and controlled to be in a secondconfiguration wherein the output of the storage system 122 is connectedto the second stage 120. For example, the one or more control valves maybe set to the first configuration during dispensing when the hydrogengas in the storage system 122 is at a higher pressure than the tank of aHFCV being refueled. The one or more control valves may be set to thesecond configuration during dispensing when the hydrogen gas in thestorage system 122 approaches, is near and/or is lower than the pressureof the tank of the HFCV being refueled. The first and secondconfigurations may correspond to a dual-mode fill capability of thehydrogen gas dispensing system, with the first configurationcorresponding to a gradient fill mode and the second configurationcorresponding to a boost fill mode, examples of which are described infurther detail below. The fill mode of the dispensing system (e.g., theconfiguration of flow control device 126) may be controlled by, forexample, one or more control signals received from the control system110.

The storage system 122 may be configured to store the hydrogen gasprovided by the hydrogen source 105 for dispensing via the dispenser106. The storage system 122 may comprise a set of one or more storagedevices such as one or more storage tanks. The storage system 122 maystore the hydrogen at a higher pressure than the hydrogen gas isprovided from the hydrogen source 105. Thus, the storage system 122 mayreceive the hydrogen gas from the compressor 116 after being compressed,as discussed above and in further detail below. For example, thehydrogen gas from hydrogen source 105 may be at a pressure below 100 PSIand the storage system 122 may store the hydrogen at a pressure up toapproximately 6,000 PSI. As discussed above, the storage system 122 maybe configured to store the hydrogen gas at a lower pressure than themaximum pressure at which hydrogen gas is dispensed. As a result, thecost, complexity, and footprint of the storage system 122 may be reducedbecause the storage system 122 does not need to be rated to withstandthe maximum pressure at which the hydrogen gas may be delivered and canbe deployed under less stringent regulatory requirements than higherpressure systems.

Further, the capacity of the storage device 122 may be limited toadvantageously minimize any safety risks posed by storing compressedhydrogen gas. For example, the storage device 122 may be constructed tostore no more hydrogen than a typical HFCV (such as 5-10 kilograms ofhydrogen). Thus, the system 100/100′ may be capable of refilling atleast one standard HFCV hydrogen tank when the HFCV is empty whileposing no greater safety risk than a conventional HFCV. Further, thestorage system 122 may be at least partially encased in a fire retardantmaterial to slow the spread of fire from the storage system 122 to othercomponents in the system 100/100′. The regulatory requirements on suchlow capacity storage systems allows for deployment of the hydrogen gasdispensing system 100/100′ in close proximity to buildings and allowsfor generally unrestricted access by consumers without breaching theapplicable safety regulations. Accordingly, limiting the size of thestorage capacity of the storage system 122 may provide any number ofadvantages, including, but not limited to smaller footprint, fewerlimitations on where the system can be located (both from a physical anda regulatory standpoint), and a reduction in cost.

The dispenser 106 may be configured to selectively couple to a vehicleand dispense hydrogen gas to a hydrogen tank on-board the vehicle. Thedispenser 106 may be, for example, configured to dispense hydrogen at apressure up to at least the maximum output pressure of the compressor116 (e.g., approximately 10,000 PSI according to some embodiments). Thedispenser 106 may comprise a nozzle (e.g., an SAE J2600 H70 Nozzle) thatselectively couples to a hydrogen gas inlet on the vehicle, a hose thatfluidly couples the nozzle to components within the system 100/100′, anda break-away component configured to allow the hose to break away fromsystem 100/100′ to prevent further damage to components of thedispensing system (e.g., in the event the vehicle moves away from thesystem 100/100′ prior to disconnecting the nozzle). Further, thedispenser 106 may include electrical components to support communicationbetween the system 100/100′ and one or more computer systems in thevehicle during refueling to get information from the vehicle, such asvehicle tank pressure, temperature, and/or fill level of the hydrogentank in the vehicle. The electrical components may be designed tocommunicate in accordance with a standard such as the J2799 standard setby the Fuel Cell Standard Committee as part of the Society of AutomotiveEngineers (SAE).

In embodiments that support electric battery charging (e.g, a hybridrefueling and recharging appliance), a power output port 108 may beconfigured to provide power to a vehicle, such as a HFCV and/or anelectric vehicle, based on power from the power input port 102. Forexample, power input port 102 and/or power output port 108 may comprisepower conversion circuitry configured to convert the power received atpower input port 102 into a suitable format for charging a battery of avehicle. The converted electrical power may be delivered to one or morepower connections provided at power output port 108 that connect to apower input connection on the vehicle. The power conversion circuitrymay be capable of providing power in a format suitable for level-1charging and/or level-2 charging. For example, if power input port 102comprises a three-phase electrical power connection and receivesthree-phase electrical power, power conversion circuitry within powerinput port 102 and/or power output port 108 may convert the powerreceived at the input port to single-phase electricity at standardhousehold levels (e.g., 120V) for level-1 charging and/or at largeappliance or industrial levels (e.g., 240V) for level-2 charging. Ifpower input port 102 receives single-phase mains electricity (either atstandard household levels and/or at large appliance/industrial levels),power conversion circuitry within power input port 102 and/or poweroutput port 108 may be configured to deliver the mains electricity tothe level-1 or level-2 power output connection, respectively, withlittle or no conversion of the input power needed. It should beappreciated that whatever the nature of the power that power input port102 is configured to receive, the appropriate power conversion circuitrymay be included in the input and/or output port to deliver theappropriate power levels at the power output port 108 to charge a HFCV,electric vehicle (EV), hybrid vehicle, etc.

According to some embodiments, a hybrid refueling and rechargingappliance comprises a power output port 108 that allows for fast DCcharging. For example, power conversion circuitry of power input port102 and/or power output port 108 may be configured to convert AC powerreceived from the power source (e.g., a three-phase source, single-phasemains electricity source, etc.) to DC power delivered to an appropriateconnector at power output port 108 to perform fast DC charging of aHFCV, EV and/or hybrid vehicle. It should be appreciated that powerconversion circuitry may be integrated into any of a variety ofcomponents within the system 100/100′ shown in FIGS. 1A and 1B (e.g.,the power input port 102 and/or the power output port 108) orimplemented in a separate component. Further, the power output by thepower conversion circuitry may be employed for additional purposesseparate from charging a vehicle to reduce the cost and complexity ofthe system 100/100′. For example, system 100/100′ may comprise powerconversion circuitry that distributes power to one or more components ofthe system (e.g., to provide power to the electrolyzer, compressor,control system, etc.).

The control system 110 may be configured to control one or morecomponents of system 100/100′ via control signals to control andcoordinate the production, storage and/or dispensing of hydrogen gas.For example, the control system may control operation of the compressor116, the flow control devices 124 and 126, and/or the electrolyzer 112.FIG. 2 shows an example implementation of the control system 110 in thesystem 100/100′. As shown, the control system 110 comprises a sensorarray 202 that is configured to measure one or more parameters withinthe system 100/100′. The output of the sensor array 202 may be employedby a control circuit 208 to control elements in the control elementarray 204. The control circuit 208 may be communicatively coupled to acontrol panel 206 that is configured to permit a user (e.g., an operatorof the vehicle) to interact with the system 100/100′. A safety circuit210 may operate independently of the control circuit 208 and shut downone or more components in the control element array 204 when the sensorarray 202 indicates that the operating conditions of the appliance100/100′ are unsafe.

The sensor array 202 may be designed to measure key parameters withinthe system 100/100′ to ensure safe operation. For example, the sensorarray 202 may comprise pressure sensor(s) 212, temperature sensor(s)214, and/or hydrogen sensor(s) 216. The pressure sensor(s) 212 may beconfigured to measure the pressure at one or more points within thesystem 100/100′, such as the pressure within the storage system 122, thepressure at the dispenser 106, the pressure within a housing of thesystem (e.g., see FIGS. 3A-3D) and/or the pressure at the flow controldevices 124 and 126. The output of the pressure sensor(s) 212 may beemployed to determine, for example, whether components within the system100/100′ are over-pressurized and likely to fail, whether components areleaking hydrogen gas, and/or a fill level of the storage system 122. Thetemperature sensor(s) 214 may be configured to measure a temperature atone or more points within the system 100/100′, such as in the storagedevice 122, within the housing, or at any other component in the system.The output of the temperature sensor(s) 214 may be employed todetermine, for example, whether components within the system 100/100′have frozen and/or whether components of the system have over-heated.The hydrogen sensor(s) 216 may be configured to sense the presence ofhydrogen at locations within the system 100/100′, such as locationswithin the housing that provides an enclosure for components of thesystem 100/100′. The output of the hydrogen sensor(s) 216 may beemployed to determine, for example, whether the components of within thesystem 100/100′ are leaking hydrogen gas and/or whether the housing isbeing properly ventilated.

The control circuit 208 may be configured to control elements within thecontrol element array 204 during normal operation of the system 100/100′to perform various functions, such as generate hydrogen gas for storage,store the hydrogen gas, and dispense the hydrogen gas to a vehicle. Thecontrol circuit 208 may perform these functions based on informationobtained from the sensor array 202 and/or information obtained from avehicle received via the dispenser 106. The control circuit 208 may beimplemented in any of a variety of ways. For example, the controlcircuit 208 may be implemented as a controller that comprises amicroprocessor (e.g., a microcontroller, field programmable gate array(FPGA), processor, etc.).

Control panel 206 may be a device that is configured to interface with ahuman user. The control panel 206 may be, for example, configured toaccept input from a user to control one or more aspects of the system(e.g., control hydrogen gas dispensing) and provide informationregarding the status of the system (e.g., the status of refueling and/orrecharging event) to the user, such as estimated fill time and/or chargetime, amount of fuel stored in the system, amount of fuel in the tank ofthe HFCV or charge on the battery of an EV, etc. The control panel 206may comprise any of a variety of interface devices, such as a touchscreen, a display, a keypad, a microphone, and a speaker.

The safety circuit 210 may be configured to control elements within thecontrol element array 204 during start-up operation of the system100/100′ for safe operation and continuously monitor the system 100/100′to identify unsafe events and shut down the system 100/100′. The safetycircuit 210 may monitor the output of the sensor array 202 and shut down(or prevent from starting) one or more components in the system 100/100′responsive to the output of one or more sensors in the sensor array 202being outside a safe operating range. The safety circuit 210 may becompletely independent from the control circuit 208 such that failure ofthe control circuit 208 does not prevent the safety circuit 210 fromensuring the safe start-up, operation and/or shut down of system100/100′. Further, the safety circuit 210 may be housed in fire and/orexplosion proof containers within the system 100/100′ to reduce thelikelihood of failing due to harsh environmental conditions (e.g., afire, an explosion, etc.). According to some embodiments, the safetycircuit is configured to control the safe start-up of the system. Forexample, upon start-up of the system, the safety circuit may beconfigured to operate only a set of components before allowing thesystem to be powered up for operation. According to some embodiments,upon start-up of the system, safety circuit 210 is configured to firstperform a number of safety checks before allowing the system to becomeoperational. For example, the safety circuit may be configured topower-on an air circulation device (e.g., one or more fans) and confirmoperation of the air circulation device before allowing the system to bepower-up. Additionally, the safety circuit may be configured to ensurenone of the sensors in a sensor array are detecting and/or measuringvalues that are outside an acceptable range. For example, safety circuit210 may be configured to prevent operation of the system until andunless pressure sensor(s) 212, temperature sensor(s) 214 and hydrogengas sensor(s) 216 each report safe operating levels. In this manner,safety circuit 210 is configured to limit start-up of the system tocircumstances where safe conditions have been confirmed.

Additionally, safety circuit 210 may be configured to shut down thesystem whenever safety circuit 210 detects an unsafe condition. Forexample, if safety circuit 210 receives indication from any of thesensors that conditions are outside an acceptable range, safety circuit210 may be configured to shut-down the system. According to someembodiments, if any of pressure sensor(s) 212, temperature sensor(s) 214or hydrogen sensor(s) 216 detect and/or measure values outside anacceptable range, safety circuit 210 may be configured to shut-down thesystem. It should be appreciated that the safety circuit may be may beimplemented in any of a variety of ways. For example, the safety circuit208 may be implemented as a controller that comprises a microprocessor.Alternatively (or additionally), safety circuit 210 may be implementedprimarily or exclusively in hardware.

Control element array 204 may comprise the elements within the system100/100′ that may be controlled by the control circuit 208 and/or thesafety circuit 210. The control element array 204 may comprise, forexample, lighting element(s) 218, heater(s) 220, flow control device(s)222 (such as flow control devices 124 and 126), and/or air circulationdevice(s). The lighting element(s) 218 may be attached on an outersurface of an enclosure that encases the system 100/100′ and have avariety of different settings (e.g., brightness, color, etc.). Thesettings of the lighting element(s) 218 may be controlled by the controlcircuit 208 to communicate information to a user. For example, thecontrol circuit 208 may change a color of the lighting element(s) 218based on a fill level of the storage system 122 to allow users toquickly evaluate whether the system 100/100′ has stored enough hydrogengas to fill their vehicle. The heaters 220 may be disposed proximate tothe storage system or hydrogen source to prevent the hydrogen sourceequipment, storage tanks or any components along or within the flow pathfrom freezing. For example, the control circuit 208 may turn on theheaters responsive to the temperature measurement received from thetemperature senor(s) 214 falling below a threshold. The flow controldevice(s) 222, such as the flow control devices 124 and 126), incombination with the compressor 116 and/or the hydrogen source 105 maybe controlled by the control circuit 208 to fill the storage system 122with hydrogen gas and/or dispense hydrogen gas via the dispenser 106 toa vehicle. The air circulation device(s) 224 may be configured tocirculate air within an enclosure that encases the system 100/100′ toensure the components remain cool. For example, the control circuit 208and/or the safety circuit 210 may turn on the air circulation device(s)224 automatically upon startup and/or in response to the temperaturesensor(s) 214 indicating that components within the system 100/100′ haveexceeded a threshold temperature.

As discussed above, the hydrogen gas dispensing system may be deployedas an integrated refueling and/or recharging appliance for HFCVs, EVs orhybrid vehicles. FIGS. 3A-3D illustrate external views of an exampleimplementation of the hydrogen gas dispensing system 100/100′ deployedas a hydrogen refueling appliance 300. The appliance 300 may be designedto have a compact footprint for placement in any of a variety oflocations. For example, the appliance 300 can be installed at anylocation having a suitable power and water connection. As shown in FIGS.3A-3D, exemplary appliance 300 may have a height of approximately 82inches, a length of approximately 100 inches, and a width ofapproximately 42.5 inches. It should be appreciated that the illustrateddimensions are non-limiting and a form factor of any suitable size andshape may be utilized.

As shown, appliance 300 comprises a housing 305 with vents 365, adisplay 380, a dispenser 370 with a nozzle 374 attached to a break awaycomponent 372, and a lighting element 382. The appliance 300 may beconfigured to dispense hydrogen gas to the storage tank of a vehicle viathe dispenser 370 that is attached to the housing 305. The dispenser 370may be an example implementation of the dispenser 106 and comprise anozzle 374 to engage with the storage tank of a vehicle and a break-awaycomponent 372 to allow the hose to break away from housing 305 withoutdamaging the internal components of the appliance 300 (e.g., in theevent a customer drives away with the nozzle still engage with thevehicle's storage tank). The appliance 300 includes multiple vents 365to allow venting of any gases within housing 305 of the appliance 300,for example, leaked hydrogen or oxygen by-product that is intentionallyvented. The shape of the housing 306, along with the location of thevents 365 and internal circulation devices (e.g., internal aircirculation devices 224) may facilitate venting of appliance 300. Forexample, the outlet vents may be placed near the top of the appliance300 because gases likely to be vented may be lighter-than-air (andthereby have a tendency to rise). Further, the inlet vents may be placednear the bottom of the appliance 300 to ensure that the air being drawnin does not contain the same gases being vented. The display 380 may bean example implementation of the control panel 206 and comprise a touchpanel that allows the appliance 300 to display information to the userand allows the user to provide information to the appliance 300.

The appliance 300 may include any or all of the components describedabove with reference to the hydrogen gas dispensing system 100/100′ thatare encased within and/or attached to the housing 305. These componentsmay be arranged within the appliance 300 in any of a variety of ways.FIG. 4 illustrates an example internal layout of the hydrogen refuelingappliance 300, in accordance with some embodiments. The exemplarydimensions are shown in FIG. 4 to illustrate a non-limiting form factorthat may be suitable for use in a wide array of installations. As shown,the appliance 300 comprises hydrogen source 410 (which may include aninternal source such as an electrolyzer and/or may include a connectionto an external source), the hydrogen storage 420 (e.g., one or morehydrogen storage tanks), a multi-stage compressor 430, and dispenser 470that together operate to produce (and/or receive), store and dispensehydrogen fuel to vehicles. It should be appreciated that appliance 300may contain additional components shown in FIGS. 1A and 1B that are notshown in FIG. 4 such as the gas purifier 144, the flow control devices124 and 126, control system 110 and/or the power output port 108.

FIG. 5 illustrates an example detailed internal layout of a hydrogenrefueling appliance 500. The appliance 500 may include any or all of thecomponents described above with reference to the hydrogen gas dispensingsystem 100/100′ and/or exemplary appliance 300 illustrated in FIGS. 3and 4. Further, the appliance 500 may have a similar form factor and/ordimensions as the appliance 300. As shown, the appliance 500 comprises abase 502 onto which a first compartment 504 and a second compartment 508may be disposed. The base 502 may raise the compartments 504 and 508 afixed distance above the ground to separate any components within thecompartments 504 and 508 from, for example, standing water or otherunsafe potential environment condition. The first compartment 504 and/orthe second compartment 508 may comprise vents 510 to safely allow theventing of gases from components disposed within the respectivecompartments. The first compartment 504 may be separated by the secondcompartment 508 by a fire retardant material 522, such as an FR-4 gradematerial, to facilitate containment of a fire within either the first orsecond compartments 504 and 508. Additionally (or alternatively), thefire retardant material 522 may at least partially encase selectcomponents within the appliance 500 to increase the inflammability ofthe appliance as needed. For example, the fire retardant material 522may at least partially encase a storage system 506 that stores hydrogengas (e.g., storage system 122) in storage devices 520.

The components of the appliance 500 may be distributed between the firstand second compartments 504 and 508 in any of a variety of ways. Asshown in FIG. 5, a hydrogen source (e.g., the hydrogen source 105) maybe disposed in the first compartment 504 and the remaining componentsmay be disposed in the second compartment 508. For example, the secondcompartment 508 may encase the storage system 506, a dispenser 514 thatdispenses hydrogen gas from the appliance, a compressor 530 thatcompresses the hydrogen gas, and an electrical enclosure 512 (e.g., anexplosion proof electrical enclosure) that holds one or more electronicdevices (e.g., the control circuit 208 and/or the safety circuit 210illustrated in FIG. 2). It should be appreciated that the components ofthe appliance 500 may be distributed in different fashions than shown inFIG. 5. However, the arrangement of components illustrated in FIG. 5provides an appliance 500 that is self-contained, has a relatively smallfootprint and meets the various regulatory requirements.

FIG. 6 illustrates an exemplary method of operating a hydrogen gasrefueling system, for example, any of the exemplary system describedherein (e.g., hydrogen gas dispensing system 100/100′, appliance 300,appliance 500, etc.). As shown, method 600 comprises a startup phase 601where the hydrogen gas dispensing system is turned on from a shutdownstate and a normal operation phase 603 where the hydrogen gas dispensingsystem is operational and may be used to dispense hydrogen gas tovehicles and/or fill onboard storage tanks with hydrogen gas. Thestartup phase 601 includes, for example, an act 602 where engaging of anair circulation device is performed, an act 604 where determiningwhether operation is safe is performed, and an act 606 where power up ofcomponents of the system is performed. The startup phase 601 may beperformed by, for example, the safety circuit 210 described inconnection with FIG. 2. The normal operation phase 603 includes, forexample, an act 608 of determining whether a vehicle is connected to thesystem, an act 610 of filling the connected vehicle, an act 612 offilling the storage system, and an act 614 of determining whether toshut down the system or remain operational. The normal operation phase603 may be performed by, for example, the control circuit 208 in thehydrogen dispensing system 100/100′ described in connection with FIG. 2.

In particular, in act 602, an air circulation device is engaged (e.g.,air circulation device(s) 224 may be engaged by safety circuit 210). Act602 may be performed by the system engaging the air circulation devicesby, for example, providing power to the air circulation device. Startingthe air circulation devices may begin the process of ventilating thesystem housing (e.g., by forcing air within the enclosure to pass byhydrogen sensors (e.g., hydrogen sensors 216) and out through exhaustvents in the housing/enclosure. As a result, the ventilationcapabilities are confirmed and the system may be better able tosubsequently read the output of these hydrogen sensors to determinewhether any component within the system has been leaking hydrogen whilethe system has been shut down.

In act 604, whether operation of the system is safe is determined. Act604 may be performed by the system determining, for example, that theoutput of the system sensors are within acceptable ranges (i.e., withina safe range). For example, the system may read one or more hydrogensensors positioned in the pathway of the air circulation devices and usethe output of the hydrogen sensors to determine whether theconcentration of hydrogen in the air is below a safe threshold. If thesystem determines that operation is not safe, the system may repeat act604 and continue to monitor the sensors to determine whether operationis safe. In act 604, additional sensors such as temperature sensors,pressure sensors, etc. may be checked to ensure that the system is safefor operation before power up the system (e.g., before proceeding to act606. Additionally, the system may send an alert regarding the detectedfault (e.g., an indication of the parameter that is outside the safeoperating range) to a maintenance team. Otherwise, the system maydetermine that operation is safe and proceed to act 606.

In act 606, components within the system are powered up to allow thesystem to become operational. For example, performing act 606 mayinclude the system providing power to all (or any portion) of thecomponents in the system. Once the components of the system have beenpowered up, the system has completed the startup phase 601 and beginsthe normal operation phase 603 by proceeding to act 608.

In act 608, whether a vehicle is connected to the system is determined.Act 608 may be performed by the system determining whether a vehicle isconnected by, for example, monitoring a pressure level in the dispenser.If the pressure detected in the dispenser is sufficiently low (e.g.,approximately that of atmospheric pressure), a vehicle is likely notconnected to the system. Conversely, if the pressure in the dispenser isabove a threshold (e.g., above approximately 25 PSI), a vehicle islikely connected to the system. Alternatively (or additionally), thesystem may determine that a vehicle is connected to the systemresponsive to detecting communication with the vehicle via conductorsintegrated into the dispenser (e.g., using a standardized protocol suchas J2799). According to some embodiments, one or more sensors may detecta mechanical coupling, an electrical connection, or both, between thedispenser and the vehicle to determine whether a vehicle is connectedand ready for refueling. If the system determines that a vehicle isconnected to the system, the system may proceed to act 610 to fill theconnected vehicle. Otherwise, the system determines that a vehicle isnot connected to the system and proceeds to act 612 of filling thestorage system as appropriate.

In act 610, hydrogen gas may be dispensed into the connected vehicle torefuel the vehicle. Act 610 may be performed by the system filling theconnected vehicle with hydrogen gas at a higher pressure than thepressure level of the hydrogen gas (if any) already in the tank of thevehicle. In a first mode, the system may dispense hydrogen gas directlyfrom the storage system in cases where the pressure of the hydrogen gasin the storage system is greater (e.g., greater by a threshold margin)than the pressure in the tank. In a second mode, the system may boostthe pressure of the hydrogen gas from the storage system using acompressor and dispense the hydrogen gas at the boosted pressure.Additional details regarding dual-mode fill techniques according to someembodiments are described below with reference to FIG. 8.

In act 612, the storage system may be filled with hydrogen gas (e.g.,storage system 122 illustrated in FIGS. 1A and 1B). Act 612 may beperformed by the system filling the storage system by, for example,compressing hydrogen gas from the hydrogen source (e.g., hydrogen source105) using a compressor (e.g., compressor 116) and storing thecompressed hydrogen gas in the storage system. Additional detailsregarding techniques for filling the storage system of a hydrogen gasrefueling appliance in accordance with some embodiments are describedbelow with reference to FIG. 7.

In act 614, it is determined whether shut down of the system is needed.For example, act 614 may be performed by the system determining whetheroperation of the system is safe and shutting down the system responsiveto detecting one or more unsafe conditions. The system may determinewhether operation is safe by, for example, checking the status of one ormore system sensors, such as one or more of hydrogen sensor(s),temperature sensor(s), pressure sensors, etc., to determine whether theoutput from the sensor(s) is within a safe range. If the systemdetermines that shutdown is needed (e.g., receives indication from oneor more sensors or components of unsafe conditions), the system powersdown components of the system and method 600 ends. For example, a safetycircuit (e.g., safety circuit 210 described in connection with FIG. 2)may monitor one or more system sensors and remove power from systemcomponents when unsafe conditions are detected (e.g., one or more sensorvalues are outside an acceptable range). As a result, a hydrogen gasdispensing system can be checked prior to start-up and during operationof the system to ensure safe operation of the refueling appliance.

FIG. 7 illustrates a method 700 of filling a storage system in ahydrogen gas dispensing system, such as the hydrogen gas dispensingsystem 100/100′. The method 700 may be performed in response to thesystem not being engaged in refueling an HFCV to renew the supply ofhydrogen available for dispensing. As shown, the method 700 comprises anact 702 of determining whether the storage system is full, an act 704 ofcompressing the hydrogen gas from the hydrogen source, an act 706 ofstoring the compressed hydrogen, an act 708 of determining whetheroperation is safe, and an act 710 of ending the storage system fill.

In act 702, the system may determine whether the storage system is full.The pressure of the hydrogen gas stored in the storage system may beproportional to the fill level of the storage system. For example, a lowpressure may be indicative of the storage system being nearly empty anda high pressure may be indicative of the storage system being full.Thereby, the system may read the output of one or more pressure sensorsin the storage system and determine the fill level. If the fill level isat or above a threshold level (e.g., 100%, 99%, 98%, etc.), the systemmay determine that the storage system is full and proceed to act 710 ofending the storage system fill. Otherwise, the system may determine thatthe storage system is not full and proceed to act 704 of compressing thehydrogen gas from the hydrogen source.

In act 704, the system may compress the hydrogen gas from the hydrogensource up to a pressure level. The system may compress the hydrogen gasup to the pressure level using, for example, a compressor that fluidlycoupled between the hydrogen source and the storage system. The pressurelevel may be between the pressure level of the hydrogen gas provided bythe hydrogen source and the maximum pressure that the hydrogen gas maybe dispensed to a vehicle. For example, the pressure level may beapproximately 6,000 PSI in implementations where the pressure from thehydrogen source is below 200 PSI and the maximum pressure the hydrogengas may be dispensed is approximately 10,000 PSI. The compressedhydrogen gas output by the compressor may be stored in the storagesystem in act 706.

In act 708, the system may determine whether operation of the system issafe. The system may determine whether operation is safe by, forexample, reading the output of sensors with the system and determiningwhether the output from the sensors is within a safe range. If thesystem determines that operation is not safe, the system may return toact 702 to determine whether the storage system is full. Otherwise, thesystem may proceed to act 710 an end the storage system fill. Forexample, act 708 may be performed using techniques described inconnection with act 614 described in connection with method 600illustrated in FIG. 6.

In act 710, the system may end the storage system fill. The system mayend the storage system fill by, for example, instructing the hydrogensource (e.g., electrolyzer) to stop producing hydrogen and controllingthe appropriate valves between the compressor and the hydrogen sourceand between the compressor and the internal storage to close.

As discussed above, the hydrogen gas dispensing systems described hereincan be used to refuel a vehicle using a dual-mode fill technique. Forexample, the dual-mode fill technique may include a gradient fill modewherein hydrogen gas is dispensed from the storage system to the vehicleand a boost fill mode wherein hydrogen gas is dispensed from the storagesystem (or the hydrogen gas source) to the vehicle via a compressor thatincreases or “boosts” the pressure of the hydrogen gas being dispensed.

FIG. 8 illustrates an exemplary dual-mode fill technique, in accordancewith some embodiments. Method 800 may be performed using, for example,the hydrogen gas dispensing systems described herein (e.g., hydrogen gasdispensing system 100/100′, appliance 300, appliance 500, etc.). Themethod 800 may be performed in response to the system being connected toa vehicle. For example, the system may detect when the nozzle of thedispenser is inserted into the tank of the vehicle and/or the nozzle orother portion of the dispenser is activated by the user (e.g., via abutton push, squeezing a trigger on the nozzle, etc.). As shown, method800 comprises an act 802 of identifying initial fill conditions andparameters, an act 804 of comparing a pressure in the storage system(P_(S)) with the pressure in the vehicle tank (P_(V)), an act 806 ofperforming a pressure gradient fill, an act 808 of performing acompressor boost fill, an act 810 of determining whether operation issafe, an act 812 of determining whether the vehicle tank is full, an act814 of identifying updated fill conditions and parameters, and an act816 of ending the vehicle fill.

In act 802, the system may identify the initial fill conditions andparameters. For example, act 802 may be performed by the systemidentifying the initial fill conditions from one or more system sensorsand/or by communicating with the vehicle. The initial fill conditionsmay comprise any of a plurality of values such as, a temperature and/orpressure of the hydrogen gas (if any) in the vehicle tank, an ambienttemperature, a fill level of hydrogen gas in the vehicle tank, and/or afill level of hydrogen gas in the storage system. The system may analyzethese initial fill conditions to identify the fill parameters. Forexample, the system may employ a look-up table that describes therelationships between fill conditions and fill parameters to identifythe fill parameters. The fill parameters may be a set of values employedto perform the vehicle refueling event. Example fill parameters includea maximum temperature for the vehicle fuel tank, a maximum hydrogendispensing rate, and/or a maximum dispensing pressure.

In act 804, the system may compare the pressure of the hydrogen storedon the storage system (P_(S)) with the tank pressure on the vehicle(P_(V)). If the pressure of the hydrogen stored in the storage system isgreater than the vehicle tank pressure (P_(S)>P_(v)) by a thresholdamount (e.g., by 1 PSI, 5 PSI, 10 PSI, etc.), the system proceeds to act806 to perform a pressure gradient fill (first mode). Otherwise, thesystem may determine that the pressure of the hydrogen stored in thestorage system is insufficient for a pressure gradient fill (e.g.,P_(S)<P_(V), P_(S) is sufficiently close to P_(V) or the systemdetermines that the fill rate is not acceptable) and proceed to act 808to perform a compressor boost fill (second mode).

In act 806, a pressure gradient fill is performed. For example, act 806may be performed by the system performing a pressure gradient fill byallowing hydrogen gas from the storage system to flow into the tank ofthe vehicle generally under the force of the existing pressure gradientbetween the storage system and the vehicle fuel tank. For example, oneor more control devices (e.g., flow control device 126) may becontrolled to allow hydrogen gas to flow from the storage system to thedispenser and into the tank of the vehicle. In such a gradient fillmode, the compressor (e.g., compressor 116) may be bypassed. The systemmay perform the gradient fill based on the identified fill parameters.For example, the system may control the rate of flow of hydrogen intothe tank based on the identified fill parameters. The gradient fill mayproceed until one or more conditions are met (e.g., P_(S)<P_(V), P_(S)is sufficiently close to P_(V) or the system determines that the fillrate is not acceptable).

In act 808, a compressor boost fill is performed. For example, act 808may be performed by the system boosting the pressure of hydrogen gasfrom the storage system (or boosting the pressure of the hydrogen gasdirectly from the hydrogen source, for example, in cases where thestorage system is sufficiently empty) using the compressor and providingthe pressurized hydrogen gas to the tank of the vehicle. For example,one or more control devices (e.g., flow control devices 124 and/or 126)may be controlled to allow hydrogen gas to flow into the compressor(e.g., compressor 116) for compression and allow the boosted hydrogengas to be provided to the dispenser and into the tank of the vehicle.The system may perform the compressor fill based on the identified fillparameters. For example, the system may control the rate of flow ofhydrogen into the tank based on the identified fill parameters. Theboost fill may continue until one or more conditions are met (e.g., thetank is filled, the dispenser is disconnected from the vehicle, etc.).The boost fill performed in act 808 provides a number of advantages,including the ability to fully fill the vehicle tank to its maximumpressure without requiring the system to store hydrogen at relativelyhigh pressures. In addition, because the system can rely on thecompressor boost, the entirety of the stored hydrogen can be dispensed,unlike systems that rely solely on a gradient fill process.

In act 810, the system may determine whether operation of the system issafe. The system may determine whether operation is safe by, forexample, monitoring system sensor(s) and determining whether the outputfrom the sensors is within a safe range. If the system determines thatoperation is not safe, the system may proceed to act 816 to end thevehicle fill. Otherwise, the system may proceed to act 812 to determinewhether the vehicle tank is full. For example, act 810 may be performedusing techniques described in connection with act 614 described inconnection with method 600 illustrated in FIG. 6.

In act 812, the system may determine whether the vehicle tank is full.The system may determine whether the vehicle tank is full based on, forexample, a pressure required to dispense additional hydrogen into thevehicle tank and/or a pressure of the hydrogen gas in the vehicle tank.These pressures may be proportional to the fill level of the tank in thevehicle. The system may thereby determine that the vehicle tank is fullresponsive to the pressure required to dispense additional hydrogen intothe vehicle tank and/or the pressure of the hydrogen gas in the vehicletank being above a threshold. Additionally (or alternatively), thesystem may determine that the vehicle tank is full based on informationobtained from the vehicle (e.g., via conductors in the dispenser thatare electrically coupled to the vehicle). For example, the system mayreceive information indicative of a fill level of the tank anddetermined that the tank is full responsive to the fill level beingabove a threshold.

As the tank of the vehicle is being filled, the fill conditions maychange. For example, the temperature of the tank of the vehicle mayincrease as the tank is being filled. Accordingly, the system mayidentify updated fill conditions and parameters in act 814. The systemmay identify the updated fill conditions by, for example, receiving datafrom one or more system sensors and/or communicating with the vehicleand, in response, generate the updated fill parameters based on theupdated fill conditions.

In act 816, the system may end the vehicle fill. The system may end thevehicle fill by, for example, controlling one or more flow controldevices to stop the dispensing of hydrogen gas to the vehicle.

FIG. 9 is a graph showing an example vehicle fill event performed by anexample hydrogen gas dispensing system. As shown, the graph includes anH2 mass dispensed line 902 indicative of the mass of the hydrogendispensed as measured in kilograms (kg), a station fill pressure line908 indicative of the pressure of the hydrogen gas being dispensed fromthe system as measured in megapascals (MPa), a J2799 communicationpressure line 906 indicative of the pressure in the tank of the vehicleobtained using the J2799 communication standard as measured in MPa, anda J2799 communication temperature line 904 indicative of the temperatureof the tank of the vehicle obtained using the J2799 communicationstandard as measured in degrees Celsius (C). The graph in FIG. 9 depictsa fill event where the tank of the vehicle was topped off (e.g., thevehicle tank is filled starting from an initial fill level of at least75%). The pressure of the hydrogen gas stored in the storage devicewithin the system is at a pressure of approximately 43 MPa while thepressure of the hydrogen in the tank is approximately 51 MPa asindicated by as indicated by the station fill pressure line 908 and theJ2799 communication pressure line 906, respectively, between 0 and 75seconds. Accordingly, the system performs a compressor fill where thepressure of the hydrogen gas from the storage device is boosted.Thereby, the station fill pressure line 908 increases to match or exceedthe J2799 communication pressure line 906 at approximately 75 secondsand hydrogen gas is dispensed. The temperature of the tank increases asthe hydrogen gas is dispensed as indicated by the J2799 communicationtemperature line 904. The hydrogen gas is dispensed until the tank isfull. In total, 1.1 kg of hydrogen gas is dispensed at an average fillrate of 25 minutes per kilogram.

FIG. 10 is a graph showing another example vehicle fill event performedby an example hydrogen gas dispensing system. As shown, the graphincludes an H2 mass dispensed line 1002 indicative of the mass of thehydrogen dispensed as measured in kg, a station fill pressure line 1008indicative of the pressure of the hydrogen gas being dispensed from thesystem as measured in MPa, a J2799 communication pressure line 1006indicative of the pressure in the tank of the vehicle obtained using theJ2799 communication standard as measured in MPa, and a J2799communication temperature line 1004 indicative of the temperature of thetank of the vehicle obtained using the J2799 communication standard asmeasured in degrees Celsius (C). The graph in FIG. 10 depicts a largerfill event that in FIG. 9 where the storage system in the hydrogen gasdispensing system is nearly depleted approximately 2,000 seconds intothe fill event. As a result, the fill rate, the rate at which hydrogengas is dispensed is lower between 2000 seconds and 3000 seconds thanbetween 0 seconds and 2000 seconds as shown by the H2 mass dispensedline 1002. The hydrogen gas is dispensed until the tank is full. Intotal, 2.1 kg of hydrogen gas is dispensed at an average fill rate of23.3 minutes per kilogram.

Having thus described several aspects and embodiments of the technologyset forth in the disclosure, it is to be appreciated that variousalterations, modifications, and improvements will readily occur to thoseskilled in the art. Such alterations, modifications, and improvementsare intended to be within the spirit and scope of the technologydescribed herein. For example, those of ordinary skill in the art willreadily envision a variety of other means and/or structures forperforming the function and/or obtaining the results and/or one or moreof the advantages described herein, and each of such variations and/ormodifications is deemed to be within the scope of the embodimentsdescribed herein. Those skilled in the art will recognize, or be able toascertain using no more than routine experimentation, many equivalentsto the specific embodiments described herein. It is, therefore, to beunderstood that the foregoing embodiments are presented by way ofexample only and that, within the scope of the appended claims andequivalents thereto, inventive embodiments may be practiced otherwisethan as specifically described. In addition, any combination of two ormore features, systems, articles, materials, kits, and/or methodsdescribed herein, if such features, systems, articles, materials, kits,and/or methods are not mutually inconsistent, is included within thescope of the present disclosure.

The above-described embodiments can be implemented in any of numerousways. One or more aspects and embodiments of the present disclosureinvolving the performance of processes or methods may utilize programinstructions executable by a device (e.g., a computer, a processor, orother device) to perform, or control performance of, the processes ormethods. In this respect, various inventive concepts may be embodied asa computer readable storage medium (or multiple computer readablestorage media) (e.g., a computer memory, one or more floppy discs,compact discs, optical discs, magnetic tapes, flash memories, circuitconfigurations in Field Programmable Gate Arrays or other semiconductordevices, or other tangible computer storage medium) encoded with one ormore programs that, when executed on one or more computers or otherprocessors, perform methods that implement one or more of the variousembodiments described above. The computer readable medium or media canbe transportable, such that the program or programs stored thereon canbe loaded onto one or more different computers or other processors toimplement various ones of the aspects described above. In someembodiments, computer readable media may be non-transitory media.

The terms “program” or “software” are used herein in a generic sense torefer to any type of computer code or set of computer-executableinstructions that can be employed to program a computer or otherprocessor to implement various aspects as described above. Additionally,it should be appreciated that according to one aspect, one or morecomputer programs that when executed perform methods of the presentdisclosure need not reside on a single computer or processor, but may bedistributed in a modular fashion among a number of different computersor processors to implement various aspects of the present disclosure.

Computer-executable instructions may be in many forms, such as programmodules, executed by one or more computers or other devices. Generally,program modules include routines, programs, objects, components, datastructures, etc. that perform particular tasks or implement particularabstract data types. Typically the functionality of the program modulesmay be combined or distributed as desired in various embodiments.

Also, data structures may be stored in computer-readable media in anysuitable form. For simplicity of illustration, data structures may beshown to have fields that are related through location in the datastructure. Such relationships may likewise be achieved by assigningstorage for the fields with locations in a computer-readable medium thatconvey relationship between the fields. However, any suitable mechanismmay be used to establish a relationship between information in fields ofa data structure, including through the use of pointers, tags or othermechanisms that establish relationship between data elements.

When implemented in software, the software code can be executed on anysuitable processor or collection of processors, whether provided in asingle computer or distributed among multiple computers.

Further, it should be appreciated that a computer may be embodied in anyof a number of forms, such as a rack-mounted computer, a desktopcomputer, a laptop computer, or a tablet computer, as non-limitingexamples. Additionally, a computer may be embedded in a device notgenerally regarded as a computer but with suitable processingcapabilities, including a Personal Digital Assistant (PDA), a smartphoneor any other suitable portable or fixed electronic device.

Also, a computer may have one or more input and output devices. Thesedevices can be used, among other things, to present a user interface.Examples of output devices that can be used to provide a user interfaceinclude printers or display screens for visual presentation of outputand speakers or other sound generating devices for audible presentationof output. Examples of input devices that can be used for a userinterface include keyboards, and pointing devices, such as mice, touchpads, and digitizing tablets. As another example, a computer may receiveinput information through speech recognition or in other audibleformats.

Such computers may be interconnected by one or more networks in anysuitable form, including a local area network or a wide area network,such as an enterprise network, and intelligent network (IN) or theInternet. Such networks may be based on any suitable technology and mayoperate according to any suitable protocol and may include wirelessnetworks, wired networks or fiber optic networks.

Also, as described, some aspects may be embodied as one or more methods.The acts performed as part of the method may be ordered in any suitableway. Accordingly, embodiments may be constructed in which acts areperformed in an order different than illustrated, which may includeperforming some acts simultaneously, even though shown as sequentialacts in illustrative embodiments.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, a reference to “A and/or B”, when usedin conjunction with open-ended language such as “comprising” can refer,in one embodiment, to A only (optionally including elements other thanB); in another embodiment, to B only (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

Also, the phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having,” “containing,” “involving,” andvariations thereof herein, is meant to encompass the items listedthereafter and equivalents thereof as well as additional items.

The terms “approximately,” “about,” and “substantially” may be used tomean within ±20% of a target value in some embodiments, within ±10% of atarget value in some embodiments, within ±5% of a target value in someembodiments, and yet within ±2% of a target value in some embodiments.The terms “approximately,” “about,” and “substantially” may include thetarget value.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” “composed of,” and the like are tobe understood to be open-ended, i.e., to mean including but not limitedto. Only the transitional phrases “consisting of” and “consistingessentially of” shall be closed or semi-closed transitional phrases,respectively.

What is claimed is:
 1. A hydrogen gas dispensing system comprising: asource configured to provide a hydrogen gas; a storage device configuredto store the hydrogen gas up to a first pressure level; a dispenserconfigured to dispense the hydrogen gas up to a second pressure levelthat is higher than the first pressure level; and a compressor fluidlycoupled to the source, the storage device, and the dispenser, thecompressor configured to compress the hydrogen gas from the source up tothe first pressure level for storage in the storage device andconfigured to compress the hydrogen gas from the storage device up tothe second pressure level for dispensing via the dispenser.
 2. Thehydrogen gas dispensing system of claim 1, further comprising acontroller configured to detect a storage pressure level of the storagedevice when a vehicle is coupled to the hydrogen gas dispensing systemvia the dispenser, the controller further configured to: cause hydrogengas to flow from the storage device to a fuel tank of the vehicle viathe dispenser when the storage pressure level is greater than athreshold pressure level; and cause hydrogen gas from the storage deviceto be compressed by the compressor before being dispensed to the fueltank of the vehicle via the dispenser when the storage pressure level isless than the threshold pressure level.
 3. The hydrogen gas dispensingsystem of claim 2, wherein the controller is configured to detect avehicle pressure level of the fuel tank of the vehicle coupled to thecoupled to the hydrogen gas dispensing system via the dispenser, andwherein the threshold pressure level is relative to the vehicle pressurelevel.
 4. The hydrogen gas dispensing system of claim 3, wherein thethreshold pressure level is substantially the vehicle pressure level ofthe fuel tank.
 5. The hydrogen gas dispensing system of claim 1, whereinthe source comprises an external source of hydrogen gas.
 6. The hydrogengas dispensing system of claim 1, wherein the first pressure level isgreater than or equal to approximately 5,000 and less than or equal toapproximately 8,000 pounds per square inch (PSI) and the second pressurelevel is greater than or equal to approximately 8,000 PSI and less thanor equal to approximately 12,000 PSI.
 7. The hydrogen gas dispensingsystem of claim 6, wherein the first pressure level is approximately6,000 pounds per square inch (PSI) and the second pressure level isapproximately 10,000 PSI.
 8. The hydrogen gas dispensing system of claim1, wherein the storage device comprises a plurality of storage tanks. 9.The hydrogen gas dispensing system of claim 1, further comprising a fireretardant material that at least partially encloses the storage device.10. The hydrogen gas dispensing system of claim 1, wherein the storagedevice is configured to store no more than approximately 10 kilograms ofhydrogen gas.
 11. The hydrogen gas dispensing system of claim 1, whereinthe source comprises an electrolyzer configured to receive water andproduce the hydrogen gas using the water.
 12. The hydrogen gasdispensing system of claim 11, further comprising a hydrogen gaspurifier fluidly coupled between the electrolyzer and the compressor,the hydrogen gas purifier being configured to remove at least someoxygen and/or at least some water from the hydrogen gas produced by theelectrolyzer.
 13. The hydrogen gas dispensing system of claim 11,further comprising: an enclosure encasing at least the storage deviceand comprising an air vent; and an air circulation device disposed inthe enclosure and configured to provide ventilation for the enclosure.14. The hydrogen gas dispensing system of claim 13, wherein the aircirculation device comprises at least one fan arranged to force air frominside the enclosure to an external environment through the air vent.15. The hydrogen gas dispensing system of claim 13, further comprising:a hydrogen gas sensor disposed in the enclosure and configured to detecthydrogen gas in the enclosure; and a circuit communicatively coupled tothe hydrogen gas sensor and configured to shut down at least onecomponent of the hydrogen gas dispensing system when a hydrogen gasconcentration detected by the hydrogen gas sensor exceeds a threshold.16. The hydrogen gas dispensing system of claim 13, further comprising:a pressure sensor disposed in the enclosure and configured to measure achange in air pressure caused by air being forced through the air vent;and a circuit communicatively coupled to the air pressure sensor andconfigured to shut down at least one component of the hydrogen gasdispensing system when an air pressure level detected by the airpressure sensor indicates an issue with air circulation.
 17. Thehydrogen gas dispensing system of claim 13, further comprising: atemperature sensor disposed in the enclosure and configured to measure atemperature of air in the enclosure; and a circuit communicativelycoupled to the temperature sensor and configured to shut down at leastone component of the hydrogen gas dispensing system when a temperaturelevel detected by the temperature sensor exceeds a threshold.
 18. Thehydrogen gas dispensing system of claim 13, further comprising: a heaterdisposed in the enclosure; a temperature sensor disposed in theenclosure and configured to measure a temperature of air in theenclosure; and a circuit communicatively coupled to the temperaturesensor and the heater, the circuit being configured to control operationof the heater based on a temperature level detected by the temperaturesensor.
 19. The hydrogen gas dispensing system of claim 13, wherein theenclosure comprises: a first compartment having at least the storagedevice disposed therein; a second compartment having at least theelectrolyzer disposed therein; and a fire retardant material disposedbetween the first compartment and the second compartment.
 20. Thehydrogen gas dispensing system of claim 13, further comprising a safetysystem for controlling powering and depowering components of thehydrogen gas dispensing system, the safety system comprising: the aircirculation device; a pressure sensor disposed in the enclosure andconfigured to measure a change in air pressure to confirm correctoperation of the air circulation device; a hydrogen gas sensor disposedin the enclosure and configured to detect hydrogen gas in the enclosure;a temperature sensor disposed in the enclosure and configured to measurea temperature of air in the enclosure; and a safety controller coupledto the pressure sensor, the hydrogen gas sensor and the temperaturesensor and configured to provide power to components of the hydrogen gasdispensing system, wherein the safety controller is configured to powerand depower components of the hydrogen gas dispensing system based, atleast in part, on indications received from the pressure sensor, thehydrogen gas sensor and the temperature sensor.
 21. The hydrogen gasdispensing system of claim 20, wherein upon power up of the hydrogen gasdispensing system, the safety controller engages the air circulationdevice, the pressure sensor, the hydrogen gas sensor and the temperaturesensor and provides operational power to other components of thehydrogen gas dispensing system only when the safety system confirms safeoperation.
 22. The hydrogen gas dispensing system of claim 20, whereinthe safety controller is configured to power down the hydrogen gasdispensing system if any of the pressure sensor, hydrogen gas sensorand/or temperature sensor signal unsafe operating conditions.
 23. Thehydrogen gas dispensing system of claim 1, wherein the hydrogen gasdispensing system is configured to provide a visual indication of a filllevel of the storage device.
 24. The hydrogen gas dispensing system ofclaim 23, further comprising: a lighting system configured to providelight in a selected one of a plurality of colors based on a controlsignal; and a circuit coupled to the lighting system and configured togenerate the control signal based on the fill level of the storagedevice.